Relying on his knees, if that is easy.

His statement, “relying on his knees, if that is easy,” means that if it is not easy for him, then he supports himself on the ground. He begins rising from prostration with his forehead and nose, then with his hands: he places them on his knees, then rises on the balls of his feet. This is the sunnah according to what the author—may Allah have mercy on him—stated, and it is the established position of the school.

Thus, we learn from his words that one does not sit when rising for the second rakʿah. This issue is also one over which there is disagreement among the hadith scholars and the jurists. (1)

The first view is that he does not sit, as the author mentioned; thus, sitting is not recommended at all. This is the established position of the school.

The second view is that he sits in all cases, whether he needs to sit or not, doing so as an act of worship to Allah, the Most High. This is the view of most hadith scholars. These are two opposing views.

The third view is a middle position: it agrees with each of the other two views in a particular case. They say that if a person needs to sit—that is, he cannot rise without sitting—then he sits as an act of worship; but if he is able to rise, he does not sit. This was the preferred view of the author of al-Mughnī (2) and Ibn al-Qayyim (3). Each of these three views has its evidence.

This sitting posture is known among the scholars as the rest sitting. It is well known that linking it to rest gives it a ruling specific to the case in which a person rests by means of it. For this reason, some rejected calling it the rest sitting.